The common name puffin describes any of three auk species (or alcids) in the bird genus Fratercula (Latin: little brother — probably a reference to their black and white plumage, which resembles monastic robes) with a brightly colored beak in the breeding season. These are pelagic seabirds that feed primarily by diving. They breed in large colonies on coastal cliffs or offshore islands, nesting in crevices among rocks or in burrows in the soil. The Tufted Puffin was formerly placed in the genus Lunda.

All three puffin species have large bills. They shed the colourful outer parts of their bills after the breeding season, leaving a smaller and duller beak. Their short wings are adapted for swimming with a flying technique under water. In the air, they beat their wings rapidly (up to 100 times per minute) in swift flight, often flying low over the ocean's surface.